Resonance merging

[Jennifer Torres 2L]

In class Professor Lavelle Stated that the true resonance structure is actually a mixture of all resonance structures I didn't quite get why that is. Could someone explain in detail.

[Kelsey Warren 1I]

I don't know how many details I can explain but I'll try! Basically what he means is that in real molecules, instead of a molecule clearly having two single bonds and one double bond (as shown by observed bond lengths), the molecule would have three bonds that were each "somewhere in between" a single bond and double bond. Another way to look at it is that in real life, it's completely irrelevant whether a certain bond is with an H on the left or top or right or middle, etc., so real molecules blend that certain bond with all of its hydrogens (as an example). Resonance shows the average of the possible chemical structures.

[Emmaraf 1K]

Lewis dot structures are inaccurate because electrons don't actually just stay stagnant in bonds but are found throughout the molecule and can move/have momentum. Therefore, the electron density at different points in time is constantly changing but on average, there is an equal electron density at each part of the molecule so the bond lengths are actually an average of each other rather than always double or single bonds.

[Linyu Zeng 1H]

I think that "bonds" can be seen as something that depicts or represents the interaction and relationship between atoms. just like force in physics. so bonds don't have to be integers like single or double. Both double or single bonds don't exist in real life. we are just trying to describe the structure of molecules as simply as possible. Resonance is like that we blends different Lewis structures of the same molecule so that we can be closer to what it's like in real life.